What is sunscreen?

     Sunscreens are products that help prevent the sun’s harmful rays from reaching the skin’s surface. The sun emits harmful rays that reach the earth’s surface. These ultraviolet rays are divided into two types: ultraviolet A (UVA) and ultraviolet B (UVB) rays. UVA rays are longer wavelength rays (320-400nm) that penetrate deep into the skins surface and are a major cause of skin aging and wrinkling. UVA rays can penetrate through glass windows and are the dominant tanning rays. It is now believed that UVA rays also contribute to the development of skin cancers. Whether exposure comes from outdoor sunlight or tanning parlor salons, UVA rays cause cumulative skin damage. UVB rays are shorter in wavelength (290-320nm) and are predominately the cause of skin reddening, sunburn and skin cancers. These rays cannot penetrate through glass windows. UVB rays also play a role in tanning and contribute to the development of fine lines, dark spots, and wrinkles.